Quantum Mechanics Supports Free Will

Quantum Mechanics Supports Free Will

Do you believe in free will?

Some physicists and neuroscientists believe in the opposite proposition: determinism. The mathematics of quantum mechanics have a say in this argument: Determinism is impossible unless you are willing to make an even greater philosophical sacrifice.

A determinist point of view says, "If I precisely know the complete workings of a system -- i.e., the position of every particle and how the laws of the universe operate -- I can tell you exactly what it will do in all future situations." For example, by measuring the sun's gravity and the motion of solar system bodies, we can calculate whether an asteroid will hit us or how to position a satellite in a complex orbit above the Earth.

Obviously, humanity has been fairly successful at this: Science and technology underpin the modern world because we largely can understand and anticipate the actions of inanimate objects.

But are you prepared to accept that your mind follows these same rules? That it is a machine which can be completely predicted, like pool balls on a felt table or comets circling a star? That you don't make choices: the choices are already made by the wiring patterns in your brain, and you just carry them out like a colossally complex adding machine? This is the philosophical endgame of classical physics (i.e., Newtonian physics) taken to its logical conclusion.

Those who accept this philosophy simply apply physics to the human brain: If we could know all the molecules and cells and what they were doing, we could predict human thought perfectly. In practice, of course, this is nearly impossible, but it is philosophically possible. And chilling.

Then along came quantum mechanics. When physicists observed that behavior at the atomic level was fundamentally indeterminate, the universal validity of classical physics, as well as philosophical determinism came into question. Physicists recoiled at the idea that their science could no longer claim to predict all things with infinite precision. But, that's what quantum mechanics teaches us. We absolutely cannot know exactly how something will turn out before it happens.

Most physicists eventually accepted this idea as an empirical fact of measurement, but assumed that a flaw in quantum mechanics created the uncertainty. Perhaps, with further insight, some "hidden variable" could allow them to predict things with perfect certainty again.

But that never happened.

John Bell, in a famous 1964 paper, forced everyone to reconsider, both scientifically and philosophically, their support for determinism. His famous theorem, Bell's inequality, is an incredibly profound statement. This relatively simple mathematical proof, when applied to experimental results, gives us a choice: We must either give up determinism or give up the existence of an objective reality explained by science and measurable by humans with instruments. (You can read the gory details about the experiments here.)

So if experiments on quantum phenomena are reliable, then Bell concludes that determinism is false. Most physicists agree.

Essentially, quantum mechanics tells us that there are things which we cannot know about the future, things which are not predetermined but happen with some factor of chance or randomness. Although many things in the world may be predicted, everything is not predetermined, and our actions do not unfold mechanically in a manner predetermined since the very moment of the Big Bang. Free will is preserved.

Thank God/gods/lucky stars!

Tom Hartsfield is a physics Ph.D. candidate at the University of Texas and a regular contributor to the RealClearScience Newton Blog. The original post appeared here.

This is what aliens would 'hear' if they flew by Earth

A Mercury-bound spacecraft's noisy flyby of our home planet.

Image source: sdecoret on Shutterstock/ESA/Big Think
Surprising Science
  • There is no sound in space, but if there was, this is what it might sound like passing by Earth.
  • A spacecraft bound for Mercury recorded data while swinging around our planet, and that data was converted into sound.
  • Yes, in space no one can hear you scream, but this is still some chill stuff.

First off, let's be clear what we mean by "hear" here. (Here, here!)

Sound, as we know it, requires air. What our ears capture is actually oscillating waves of fluctuating air pressure. Cilia, fibers in our ears, respond to these fluctuations by firing off corresponding clusters of tones at different pitches to our brains. This is what we perceive as sound.

All of which is to say, sound requires air, and space is notoriously void of that. So, in terms of human-perceivable sound, it's silent out there. Nonetheless, there can be cyclical events in space — such as oscillating values in streams of captured data — that can be mapped to pitches, and thus made audible.


Image source: European Space Agency

The European Space Agency's BepiColombo spacecraft took off from Kourou, French Guyana on October 20, 2019, on its way to Mercury. To reduce its speed for the proper trajectory to Mercury, BepiColombo executed a "gravity-assist flyby," slinging itself around the Earth before leaving home. Over the course of its 34-minute flyby, its two data recorders captured five data sets that Italy's National Institute for Astrophysics (INAF) enhanced and converted into sound waves.

Into and out of Earth's shadow

In April, BepiColombo began its closest approach to Earth, ranging from 256,393 kilometers (159,315 miles) to 129,488 kilometers (80,460 miles) away. The audio above starts as BepiColombo begins to sneak into the Earth's shadow facing away from the sun.

The data was captured by BepiColombo's Italian Spring Accelerometer (ISA) instrument. Says Carmelo Magnafico of the ISA team, "When the spacecraft enters the shadow and the force of the Sun disappears, we can hear a slight vibration. The solar panels, previously flexed by the Sun, then find a new balance. Upon exiting the shadow, we can hear the effect again."

In addition to making for some cool sounds, the phenomenon allowed the ISA team to confirm just how sensitive their instrument is. "This is an extraordinary situation," says Carmelo. "Since we started the cruise, we have only been in direct sunshine, so we did not have the possibility to check effectively whether our instrument is measuring the variations of the force of the sunlight."

When the craft arrives at Mercury, the ISA will be tasked with studying the planets gravity.

Magentosphere melody

The second clip is derived from data captured by BepiColombo's MPO-MAG magnetometer, AKA MERMAG, as the craft traveled through Earth's magnetosphere, the area surrounding the planet that's determined by the its magnetic field.

BepiColombo eventually entered the hellish mangentosheath, the region battered by cosmic plasma from the sun before the craft passed into the relatively peaceful magentopause that marks the transition between the magnetosphere and Earth's own magnetic field.

MERMAG will map Mercury's magnetosphere, as well as the magnetic state of the planet's interior. As a secondary objective, it will assess the interaction of the solar wind, Mercury's magnetic field, and the planet, analyzing the dynamics of the magnetosphere and its interaction with Mercury.

Recording session over, BepiColombo is now slipping through space silently with its arrival at Mercury planned for 2025.

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Research suggests that aging affects a brain circuit critical for learning and decision-making.

Photo by Reinhart Julian on Unsplash
Mind & Brain

As people age, they often lose their motivation to learn new things or engage in everyday activities. In a study of mice, MIT neuroscientists have now identified a brain circuit that is critical for maintaining this kind of motivation.

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  • The scientists show that tides created tidal pools, stranding fish and forcing them to get out of the water.
  • The researchers ran computer simulations to get their results.
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